Exactly, there is no limit. If its food, then it goes to the chickens and they get the final say.
Everything goes to them and they make the best tasting eggs you have ever had from those leftovers.
We were even partial to asking people in restaurants if we could take their leftovers. We had a grocery store that sold us partially rotten bits too. Them where the chickens favorites, bugs and all.
"Throw it all in the coop and let the Chickens sort it out."
Other than green potato peels, which are unsafe for about everything there isnt anything I can think of that passes through a kitchen which is unsafe or not recommended for a chicken coop.
EDIT:
As for meat, they LOVE meat. Double so chicken meat. The only worry is to feed them raw egg.
Even that is a-ok unless they make the link between what they lay and what they tasted. Still better off to cook it and not have the chance of starting an egg eater.
Everything loves to eat chicken, even chickens. Here's a T-Shirt I wanted to sell more of